U.S. patent application number 12/033879 was filed with the patent office on 2008-08-21 for passage composite, an ink jet head and a printer.
Invention is credited to Tadanobu Chikamoto, Yuji Mizoguchi.
Application Number | 20080198209 12/033879 |
Document ID | / |
Family ID | 39706269 |
Filed Date | 2008-08-21 |
United States Patent
Application |
20080198209 |
Kind Code |
A1 |
Mizoguchi; Yuji ; et
al. |
August 21, 2008 |
PASSAGE COMPOSITE, AN INK JET HEAD AND A PRINTER
Abstract
A printer has an inkjet head, which has a passage composite. The
passage composite has a main body, having a surface and a
projection portion that extends outward from the surface. The
projection portion has an opening formed through it, and the
projection portion also has an end, and an edge opposite the end.
The main body also has at least one rib positioned outside the
projection portion. The at least one rib extends away from the
surface, and is separated by a predetermined nonzero distance from
the edge of the projection portion.
Inventors: |
Mizoguchi; Yuji; (Kani-shi,
JP) ; Chikamoto; Tadanobu; (Nagoya-shi, JP) |
Correspondence
Address: |
BAKER BOTTS LLP;C/O INTELLECTUAL PROPERTY DEPARTMENT
THE WARNER, SUITE 1300, 1299 PENNSYLVANIA AVE, NW
WASHINGTON
DC
20004-2400
US
|
Family ID: |
39706269 |
Appl. No.: |
12/033879 |
Filed: |
February 19, 2008 |
Current U.S.
Class: |
347/85 |
Current CPC
Class: |
B41J 2/14209 20130101;
B41J 2002/14225 20130101; B41J 2202/12 20130101; B41J 2002/14217
20130101; B41J 2002/14459 20130101; B41J 2002/14306 20130101; B41J
2002/14419 20130101; B41J 2202/11 20130101; B41J 2202/20
20130101 |
Class at
Publication: |
347/85 |
International
Class: |
B41J 2/175 20060101
B41J002/175 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 19, 2007 |
JP |
2007038366 |
Claims
1. A passage composite comprising: a main body comprising: a
particular surface; a passage projection portion extending away
from the particular surface and comprising a particular end, an
edge opposite the particular end, and an opening formed
therethrough; and at least one rib positioned outside the passage
projection portion, and extending away from the particular surface,
wherein at least a portion of the at least one rib is positioned a
predetermined nonzero distance from the edge of the passage
projection portion.
2. The passage composite of claim 1, further comprising a film
welded to the edge of the passage projection portion, and
configured to close the opening formed in the passage projection
portion.
3. The passage composite of claim 1, wherein the at least one rib
is connected to the passage projection projection.
4. The passage composite of claim 1, wherein the rib comprises a
first segment, wherein at least a portion of the passage projection
portion extends further away from the particular surface than the
first segment.
5. The passage composite of claim 4, wherein the rib further
comprises a second segment, and wherein the second segment extends
further away from the particular surface than the first segment,
and the first segment is positioned between the passage projection
portion and the second segment.
6. The passage composite of claim 5, wherein the second segment
extends further away from the particular surface than the passage
projection portion.
7. The passage composite of claim 6, wherein the passage projection
portion is substantially oval-shaped.
8. The passage composite of claim 1, wherein the edge opposite the
first end is a substantially flat surface.
9. The passage composite of claim 1, wherein the passage projection
portion tapers away from the first surface towards the second
edge.
10. The passage composite of claim 1, wherein the main body further
comprises: a further surface opposite the particular surface; a
connection projection portion extending away from the further
surface, and comprising a further end, a further edge opposite the
further end, and a further opening formed therethrough; and at
least one connection rib positioned outside the connection
projection portion, and extending away from the further surface,
wherein at least a portion of the at least one connection rib is
positioned a predetermined nonzero distance from the edge of the
connection projection portion.
11. The passage composite of claim 10, further comprising a further
film welded to the further edge of the connection projection
portion, and configured to close the further opening formed in the
connection projection portion.
12. The passage composite of claim 10, further comprising: an inlet
valve configured to be in fluid communication with the passage
projection portion; and an outlet valve configured to be in fluid
communication with the connection projection portion.
13. An ink jet head comprising a passage composite, the passage
composite comprising: a main body comprising: a particular surface;
a passage projection portion extending away from the particular
surface and comprising a particular end, an edge opposite the
particular end, and an opening formed therethrough; and at least
one rib positioned outside the passage projection portion, and
extending away from the particular surface, wherein at least a
portion of the at least one rib is positioned a predetermined
nonzero distance from the edge of the passage projection
portion.
14. The ink jet head of claim 13, wherein the main body further
comprises: a further surface opposite the particular surface; a
connection projection portion extending away from the further
surface, and comprising a further end, a further edge opposite the
further end, and a further opening formed therethrough; and at
least one connection rib positioned outside the connection
projection portion, and extending away from the further surface,
wherein at least a portion of the at least one connection rib is
positioned a predetermined nonzero distance from the edge of the
connection projection portion.
15. The ink jet head of claim 13, further comprising an inlet valve
configured to be in fluid communication with the passage projection
portion; and an outlet valve configured to be in fluid
communication with the connection projection portion.
16. The ink jet head of claim 13, further comprising: a substrate
configured to receive electrical components; a reservoir unit
configured to receive and to supply ink; at least one ink supply
port configured to be in fluid communication with the lower
reservoir; a passage unit configured to receive ink from the at
least one ink supply port; and at least one nozzle configured to
eject ink supplied from the passage unit, wherein the inlet valve
is configured to supply ink to the passage projection portion, the
passage projection portion is configured to be in fluid
communication with the connection projection portion, and and the
outlet valve is configured to supply ink to the lower
reservoir.
17. A printer comprising: an ink cartridge configured to supply
ink; and an ink jet head comprising a passage composite, the
passage composite comprising: a main body comprising: a particular
surface; a passage projection portion extending away from the
particular surface and comprising a particular end, an edge
opposite the particular end, and an opening formed therethrough;
and at least one rib positioned outside the passage projection
portion, and extending away from the particular surface, wherein at
least a portion of the at least one rib is positioned a
predetermined nonzero distance from the edge of the passage
projection portion.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application claims priority from Japanese Patent
Application No. 2007-038366, which was filed on Feb. 19, 2007, the
disclosure of which is herein incorporated in its entirety by
reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a passage composite, and
the use of a passage composite in an ink jet head and in a
printer.
[0004] 2. Description of the Related Art
[0005] Known ink jet heads for ejecting ink from nozzles to a sheet
of paper each include a passage unit having a plurality of
individual ink passages extending to nozzles arranged on the bottom
surface of the ink jet head, and a reservoir unit that temporarily
stores ink and supplies the ink to the passage unit.
[0006] In the known ink jet heads, the reservoir unit has a
laminate structure including a passage block and three metal
plates. The passage block is long in the main scanning direction
and is made of a thermoplastic resin. Each metal plate has a
rectangular planar surface that is long in the main scanning
direction. The reservoir unit has an ink passage therein. The
passage block has a loop projection and defines at least part of a
passage opening closed by a film. The passage block has ribs
projecting perpendicular to the first surface. Some of the ribs are
connected to the outer surface of the loop projection.
SUMMARY OF THE INVENTION
[0007] Accordingly, it is an object of the present invention to
provide a passage composite in which an operation of arranging a
film can easily and efficiently be performed and which ensures
improvement of yield. In an embodiment of the invention, a passage
composite comprises a main body comprising, the main body
comprising a particular surface, a passage projection portion
extending away from the particular surface and comprising a
particular end, an edge opposite the particular end, and an opening
formed therethrough, and at least one rib positioned outside the
passage projection portion, and extending away from the particular
surface, wherein at least a portion of the at least one rib is
positioned a predetermined nonzero distance from the edge of the
passage projection portion.
[0008] In another embodiment of the invention, an ink jet head
comprises a passage composite. The passage composite comprises a
main body, which comprises a particular surface, a passage
projection portion extending away from the particular surface and
comprising a particular end, an edge opposite the particular end,
and an opening formed therethrough, and at least one rib positioned
outside the passage projection portion, and extending away from the
particular surface, wherein at least a portion of the at least one
rib is positioned a predetermined nonzero distance from the edge of
the passage projection portion.
[0009] In yet another embodiment of the invention, a printer
comprises an ink cartridge configured to supply ink, and an ink jet
head comprising a passage composite, the passage composite
comprising a main body. The main body comprises a particular
surface, a passage projection portion extending away from the
particular surface and comprising a particular end, an edge
opposite the particular end, and an opening formed therethrough,
and at least one rib positioned outside the passage projection
portion, and extending away from the particular surface, wherein at
least a portion of the at least one rib is positioned a
predetermined nonzero distance from the edge of the passage
projection portion.
[0010] Other objects, features, and advantages will be apparent to
persons of ordinary skill in the art from the following detailed
description of the invention and the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] For a more complete understanding of the present invention,
needs satisfied thereby, and the objects, features, and advantages
thereof, reference now is made to the following description taken
in connection with the accompanying drawing.
[0012] FIG. 1 is a perspective view of an ink jet head according to
an embodiment of the invention.
[0013] FIG. 2 is a longitudinal sectional view of a reservoir unit
shown in FIG. 1 according to an embodiment of the invention.
[0014] FIG. 3A is a top view of a main body of an upper reservoir
block shown in FIG. 2, according to an embodiment of the present
invention.
[0015] FIG. 3B is a bottom view of the main body shown in FIG.
3A.
[0016] FIG. 4 is a perspective view of the main body of the upper
reservoir block in FIG. 2, when viewed from above.
[0017] FIG. 5 is a perspective view of the main body of the upper
reservoir block in FIG. 2, when viewed from below.
[0018] FIGS. 6A to 6C are diagrams illustrating a procedure for
welding a filter shown in FIG. 2 to the main body, according to an
embodiment of the invention.
[0019] FIG. 7 is a plan view of a passage unit shown in FIG. 1,
according to an embodiment of the invention.
[0020] FIG. 8 is an enlarged view of part surrounded by an
alternate long and short dash line in FIG. 7.
[0021] FIG. 9 is a partially cross-sectional view taken along the
line IX-IX in FIG. 8.
[0022] FIG. 10A is an enlarged cross-sectional view of an actuator
unit shown in FIG. 9.
[0023] FIG. 10B is a plan view of an individual electrode arranged
on one surface of the actuator unit in FIG. 10A.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0024] Embodiments of the present invention, and their features and
advantages, are understood by referring to FIGS. 1-10B, with like
numerals being used for like corresponding parts in the various
drawings.
[0025] FIG. 1 may be an external perspective view of an ink jet
head according to an embodiment. Referring to FIG. 1, an ink jet
head 1, may have a substantially rectangular shape, and the longer
sides of ink jet head 1 may extend in the main scanning direction.
Ink jet head 1 may include, in order from the bottom, a passage
unit 5, a reservoir unit 3, and a substrate 2. Referring to FIG. 9,
passage unit 5 may include a plurality of individual ink passages
60, which may be in fluid communication with a plurality of nozzles
8. Referring back to FIG. 1, reservoir unit 3 temporarily may store
ink and may supply the ink to passage unit 5. The substrate 2 may
be mounted with electronic components, such as connectors 2a and
capacitors 2b. With reference to the following description and the
associated drawings, one side of the ink jet head 1, e.g., the side
in which the passage unit 5 may be arranged, will be
interchangeably referred to as a "lower side." Another side, e.g.,
the side in which the substrate 2 may be arranged will be
interchangeably referred to as an "upper side."
[0026] Referring now to FIG. 7, a plurality of, e.g., four,
actuator units 7 may be fixed to an upper surface 5a of the passage
unit 5. Flexible printed circuits (FPCs) 6, which may function as
interconnecting members attached to the respective actuator units
7, may extend from between the passage unit 5 and the reservoir
unit 3, in an upward direction along the side surfaces of the
reservoir unit 3. FPCs 6 may be connected to the respective
connectors 2a on the substrate 2. Each FPC 6 may be mounted with a
driver IC 6a. Driver IC 6a may be positioned between the
corresponding actuator unit 7 and the substrate 2. In other words,
each FPC 6 may be electrically connected to both of the substrate 2
and the driver IC 6a. Accordingly, the FPC 6 may transmit an image
signal output from the substrate 2 to the corresponding driver IC
6a, and may supply a drive signal output from the driver IC 6a to
the actuator unit 7. Referring to FIG. 2, the the ink jet head is
enlarged in the vertical direction, and passages which may not
appear in the plane shown in the sectional view of FIG. 2, are
shown in FIG. 2.
[0027] Reservoir unit 3 may have a laminate structure containing
the upper reservoir block 11 extending in the main scanning
direction, and a plurality, e.g., three, plates 16, 17, and 18
extending in the main scanning direction. The plates 16 to 18 may
be plates made of metal, e.g., stainless steel. The laminated
plates 16 to 18 may constitute a lower reservoir block 15 of the
reservoir unit 3.
[0028] The upper reservoir block 11 may be made of a thermoplastic
resin, e.g., polyacetal or polypropylene. Upper reservoir block 11
may includes the main body 12 extending in the main scanning
direction, and films 13 and 14, which may be welded to the main
body 12. Upper reservoir block 11 may have an inlet port 21, an
outlet port 22, and an upper reservoir passage 25. Outlet port 22
may be arranged substantially in the center of the main body 12 in
the lengthwise direction thereof The inlet port 21 may be in fluid
communication with a space over the main body 12. The outlet port
22 may be in fluid communication with a space under the main body
12. The upper reservoir passage 25 may connect the inlet port 21 to
the outlet port 22. In other words, the upper reservoir passage 25
may be arranged between the center and one end of the upper
reservoir block 11 in the lengthwise direction thereof.
[0029] A cylindrical joint 20 surrounding the inlet port 21 and
extending upward may be arranged on an upper reference surface 12a,
e.g., a first surface of the main body 12, and may face upward. The
joint 20 may be connected to a connecting member coupled to one end
of an ink supply tube (not shown) connected to an ink tank (not
shown). With the above-described arrangement, ink may be supplied
from the ink tank to the upper reservoir passage 25 via the joint
20.
[0030] Part of the main body 12 may serve as the wall surface of
the upper reservoir passage 25, and may constitute a protuberance
31 raised upward from the upper reference surface 12a. A side wall
33 of the protuberance 31 may be a loop projection projecting
upward from the upper reference surface 12a. More specifically, the
protuberance 31 may be arranged between the outlet port 22 and the
vicinity of the center of the upper reservoir passage 25.
Proturberance 31 may extend in the lengthwise direction of the
upper reservoir block 11, e.g., the main scanning direction.
[0031] Referring to FIGS. 3A and 4, the protuberance 31, when
viewed in a plan view, may have a wide portion 32a, which may be
substantially oval shaped, and a narrow portion 32b. The width,
e.g., the portion extending in the sub-scanning direction, of the
wide portion 32a, may spread close to both ends of the main body
12, in the widthwise direction of the main body 12. The narrow
portion 32b may be located in the vicinity of one end of the
protuberance 31, facing the outlet port 22. The width of the narrow
portion 32b may be narrower than that of the wide portion 32a.
[0032] In the protuberance 31, the narrow portion 32b may have a
passage opening 34, which may extend in a first direction
perpendicular to the upper reference surface 12a, and which may be
elongated in the main scanning direction. The edge of the side wall
33, which may extend perpendicular to the upper reference surface
12a of the protuberance 31, may partially define the passage
opening 34. Referring back to FIG. 2, the passage opening 34 may be
closed by the film 13. In other words, the space surrounded by the
film 13 and the inner surface 33c of the loop side wall 33 may
serve as part of the upper reservoir passage 25.
[0033] The protuberance 31 may allow the depth, e.g., the height in
the vertical direction in FIG. 2, of the upper reservoir passage 25
to be increased, in a portion between the vicinity of the outlet
port 22 and the vicinity of the center of the upper reservoir
passage 25, in the lengthwise direction thereof A filter 10 may be
positioned in such a deep portion, perpendicularly to the vertical
direction in FIG. 2. Ink, which may be supplied from the inlet port
21 into the upper reservoir passage 25, may flow upward in the deep
portion, while passing through the filter 10, and then may flow out
of the outlet port 22.
[0034] Part of the main body 12 may constitute a loop projection
41. Loop projection 41 may project downward from a lower reference
surface 12b. Specifically, the loop projection 41 may surround a
region extending from the inlet port 21 of the upper reservoir
passage 25 to the vicinity of the outlet port 22. Referring now to
FIGS. 3B and 5, the loop projection 41, when viewed in a plan view,
may have a substantially oval-shaped wide portion 42a, and a narrow
portion 42b. An area of wide portion 42a may be larger than an area
of wide portion 32a of the protuberance 31 on the opposite side.
The narrow portion 42b may extend from a first end of the loop
projection 41 facing the inlet port 21 to one end of the wide
portion 42a adjacent to the first end of the loop projection 41.
The width of the narrow portion 42b may be narrower than the width
of the wide portion 42a. The edge of the loop projection 41 may
define a passage opening 44, which may extend in the first
direction, perpendicular to the lower reference surface 12b.
Referring back to FIG. 2, the passage opening 44 may be closed by
the film 14. In other words, the space formed by the film 14 and
the inner surface 41c of the loop projection 41 may serve as part
of the upper reservoir passage 25.
[0035] Referring again to FIGS. 3A to 5, each of which show a state
in which the films 13 and 14 may be not arranged, the upper end of
the protuberance 31 surrounding the passage opening 34 may be
tapered to provide a tapered portion 33a. The downward projecting
end of the loop projection 41 surrounding the passage opening 44
may be tapered to form a tapered portion 41a. The tapered portions
33a and 41a may be configured to be melted when the films 13 and
14, for closing the passage openings 34 and 44, are welded to the
main body 12. Referring to FIG. 3A, a portion of main body 12,
e.g., the portion surrounding passage opening 34, may be configured
to be welded to the film 13. Referring to FIG. 3B, a portion of
main body 12, e.g., the portion surrounding passage opening 44,
which is a hatched portion of FIG. 3B, may be configured to be
welded to the film 14. In this manner, the passage openings 34 and
44 may be closed by the films 13 and 14, respectively.
[0036] Referring to FIG. 6A, a rolled film 90 may be unrolled, and
may be pressed against the tapered portion 41a, thus covering the
passage opening 44 with the film 90. Subsequently, the tapered
portion 41a may be melted by heating through the film 90. Referring
to FIG. 6B, the film 90 may be welded to the loop projection 41.
After that, the film 90 may be cut along the outer surface 41b of
the loop projection 41 using a cutting tool, e.g., a cutter or a
laser beam, to remove the excess film 90. Consequently, referring
to FIG. 6C, the passage opening 44 may be covered with the film 14.
6C. Film 13 may be welded according to a similar procedure, thus an
explanation of the procedure for welding film 13 is omitted.
[0037] The films 13 and 14 each may comprise a flexible material
having a gas barrier property, e.g., a polyethylene terephtharate
(PET) film with a vapor-deposited silica (SiOx) or aluminum layer.
Accordingly, a gas outside the ink jet head 1 may be substantially
prevented from entering the upper reservoir passage 25 in the upper
reservoir block 11 through the films 13 and 14.
[0038] As described above, the flexible films 13 and 14 may define
portions of the upper reservoir passage 25. Accordingly, films 13
and 14 may absorb abrupt variations in pressure exerted on ink in
the upper reservoir passage 25, by deforming in response to the
abrupt variations in pressure exerted on the ink. In other words,
the films 13 and 14 each may function as a damper. Consequently,
ink may flow smoothly in the upper reservoir passage 25, and the
ink ejecting property may be stabilized. Referring back to FIG. 2,
the film 14 may be positioned at a slight distance from the upper
surface of the lower reservoir block 15, or the plate 16, so as not
to impair the damper function of film 14.
[0039] The upper reference surface 12a may be provided with a
plurality of ribs 35, which may upwardly project perpendicular to
the upper reference surface 12a, and may extend in the main
scanning and sub-scanning directions. In other words, the ribs 35
may be arranged substantially in a lattice. The lower reference
surface 12b similarly may be provided with a plurality of ribs 45
arranged substantially in a lattice, the ribs 45 downwardly
projecting perpendicular to the lower reference surface 12b. The
arrangement of the ribs 35 and 45 may increase the solidity of the
upper reservoir block 11, which may prevent the upper reservoir
block 11 from deforming.
[0040] Referring back to FIGS. 6A to 6C, the level of each rib 45,
relative to the lower reference surface 12b, hereinafter,
interchangeably referred to as "the level of each rib 45" may be
slightly lower than the level of the loop projection 41, relative
to the lower reference surface 12b, hereinafter, interchangeably
referred to as "the level of the loop projection 41", after
completion of melting the tapered portion 41a. Each of the ribs 45
connected to the outer surface 41b of the loop projection 41,
hereinafter interchangeably referred to as the specific notched
ribs, may have a notch 45a in its upper end, and may be positioned
such that the notch 45a is next to the outer surface 41b. Rib 45
may be divided into a first segment 46 and a second segment 47 in
its extending direction, e.g., the sub-scanning direction as shown
in FIGS. 6A to 6C, such that the first segment 46 may connect to
the outer surface 41b of the loop projection 41. Notch 45a and the
second segment 47 may be positioned on the opposite side of the
first segment 46 relative to the loop projection 41. Further, the
level of the first segment 46 of the rib 45 may be lower than the
level of the loop projection 41. In other words, the rib 45 may be
separated from the end of the loop projection 41. In addition, the
level of the second segment 47 of the rib 45 may be higher than
that of the first segment 46.
[0041] Referring again to FIGS. 3A and 4, the ribs 35 may be
coupled to the side wall 33 of the protuberance 31, and each rib 35
may have a similar notch 35a. Specifically, the notch 35a, in each
of the ribs 35, may be arranged in a first segment 36, which may
connect to the external surface 33b. External surface 33b may be a
portion of the side wall 33 of the protuberance 31, e.g., the
portion defining the passage opening 34. Consequently, each rib 35
may be separated from the end of the side wall 33 of the
protuberance 31. A second segment 37 may be disposed on the
opposite side of the first segment 36 relative to the side wall 33.
In addition, the level of a second segment 37 of the rib 35,
relative to the upper reference surface 12a, may be higher than
that of the first segment 36. The level of the rib 35 relative to
the upper reference surface 12a hereinafter may be interchangeably
referred to as "the level of the rib 35."
[0042] Referring again to FIG. 2, among the plates 16 to 18, the
upper plate 16 may have a through hole located substantially at the
center thereof, which may serve as a downward passage 16a. Downward
passage 16a may be in fluid communication with the upper reservoir
passage 25, via the outlet port 22. The lower plate 18 may have a
plurality of, e.g., ten, through holes, which may serve as supply
passages 18a. Referring to FIG. 7, supply passages 18a may be in
fluid communication with respective ink supply ports 9, which may
be arranged in the passage unit 5. Referring back to FIG. 2, the
intermediate plate 17 may have a hole, which may serve as a
reservoir 17a. Reservoir 17a may be in fluid communication with the
downward passage 16a and the plurality of supply passages 18a. The
downward passage 16a, the reservoir 17a, and the supply passages
18a may constitute a lower reservoir passage 27.
[0043] As indicated by the solid arrows in FIG. 2, which indicate
the flow of ink in the reservoir unit 3, ink supplied from the
inlet port 21 into the upper reservoir passage 25 may flow
downward, and then may flow in the main scanning direction. At that
time, the ink flowing in the main scanning direction may travel
upward while passing through the filter 10, and again may flow
downward in the center of the upper reservoir block 11. Ink flowing
in the main scanning direction then may flow outward from the
outlet port 22 into the downward passage 16a constituting the lower
reservoir passage 27. In the lower reservoir passage 27, the ink
may flow from the outlet port 22 of the upper reservoir passage 25
into the reservoir 17a via the downward passage 16a. In the
reservoir 17a, the ink may reach the respective supply passages
18a. Referring now to FIG. 7, once ink reaches the respective
supply passages 18a, ink may be supplied to the passage unit 5 via
the respective ink supply ports 9.
[0044] As described above, the reservoir unit 3 may have a series
of ink passages, such as the upper reservoir passage 25 and the
lower reservoir passage 27. These ink passages may function as an
ink reservoir for temporarily storing ink.
In FIG. 8, pressure chambers 53, apertures 55, and the nozzles 8
should be drawn using dashed lines because they are located under
the actuator units 7. Nevertheless, in FIG. 8, the pressure
chambers 53, the apertures 55, and the nozzles 8 are drawn using
solid lines to facilitate understanding of the drawings.
[0045] Referring to FIG. 8, the passage unit 5 may be a rectangular
solid having substantially the same planar shape as that of the
plate 18 in the reservoir unit 3. The four actuator units 7 may
have a trapezoidal planar shape, and may be arranged on the upper
surface 5a facing the reservoir unit 3.
[0046] The upper surface 5a of the passage unit 5 may contain the
plurality of ink supply ports 9. Referring back to FIG. 2, the
plurality of ink supply ports 9 correspond to the respective supply
passages 18a of the reservoir unit 3. Referring again to FIG. 9,
the passage unit 5 may have manifold passages 51 in fluid
communication with the ink supply ports 9, and sub-manifold
passages 51 a branching off from the manifold passages 51. In the
lower surface of the passage unit 5, ink ejecting areas 5b may be
arranged opposite to the respective actuator units 7, with the
passage unit 5 therebetween. Referring to FIG. 8, the plurality of
nozzles 8 may be arranged in each ink ejecting area 5b in a matrix
pattern. Referring again to FIG. 9, in the upper surface 5a of the
passage unit 5, the many pressure chambers 53 may be arranged in a
matrix pattern in each of areas facing the respective actuator
units 7.
[0047] In an embodiment of the invention, as shown in FIG. 8, a
plurality of, e.g., sixteen, rows of the pressure chambers 53 may
be substantially equally spaced in the lengthwise direction, e.g.,
the horizontal direction as shown in FIG. 8, or the main scanning
direction, of the passage unit 5 may be arranged in parallel in the
widthwise direction, e.g., the vertical direction in FIG. 8, or the
sub-scanning direction, of the passage unit 5 in each of areas
facing the respective actuator units 7. The pressure chambers 53
may be disposed in each of the areas such that the number of
pressure chambers 53 in each row may gradually decrease, and each
row may correspond to the trapezoidal shape of the actuator unit 7,
e.g., as the rows become closer to the shorter side of the
trapezoid. The adjacent actuator units 7 may be equally spaced,
such that the opposed sides of the actuator units 7 may be parallel
to each other and the actuator units 7 are staggered. In aligning
parts of the adjacent actuator units 7, the pressure chambers 53
may be arranged in complementary relationship, with respect to the
lateral direction in FIG. 8.
[0048] Referring to FIG. 9, the passage unit 5 may include a
plurality of, e.g., nine, plates made of metal, e.g., stainless
steel. Specifically, the passage unit 5 includes, in order from the
top, a cavity plate 61, a base plate 62, an aperture plate 63, a
supply plate 64, manifold plates 65, 66, and 67, a cover plate 68,
and a nozzle plate 69. Plates 61 to 69 each may have a rectangular
planar surface in which the longer sides of the rectangular planar
surface extend in the main scanning direction.
[0049] The cavity plate 61 may have a plurality of substantially
rhomboid-shaped through holes, which may correspond to the
respective pressure chambers 53. The aperture plate 63 may include
the apertures 55, which may be in fluid communication with the
respective pressure chambers 53 via connecting holes formed in the
base plate 62. The manifold plates 65, 66, and 67 may have one or
more through holes, which may be coupled to each other. The through
holes in manifold plates 65, 66, and 67 may provide the manifold
passages 51 and the sub-manifold passages 51a when the manifold
plates 65, 66, and 67 are laminated. The sub-manifold passages 51a
may be in fluid communication with the respective apertures 55 via
connecting holes formed in the supply plate 64. The nozzle plate 69
may have one or more holes corresponding to the respective nozzles
8 for the pressure chambers 53. The plates 61 to 64 may have
connecting holes (not shown) for connecting the ink supply ports 9
with the manifold passages 51. Furthermore, the plates 62 to 68 may
have connecting holes for connecting the pressure chambers 53 with
the nozzles 8.
[0050] These plates 61 to 69 may be laminated while being aligned
with respect to each other, such that the manifold passages 51, the
sub-manifold passages 51a, and the many individual ink passages 60
may be formed to extend from the outlets of the sub-manifold
passages 51a to the respective nozzles 8 through the apertures 55
and the pressure chambers 53. Consequently, ink supplied from the
reservoir unit 3 into the passage unit 5 via the ink supply ports 9
may flow into the manifold passages 51, and further may flow into
the sub-manifold passages 51a branching off from the manifold
passages 51. The supplied ink further may flow into the individual
ink passages 60, such that the ink reaches the respective nozzles
8.
[0051] Referring to FIG. 7, the plurality of actuator units 7 may
have a trapezoidal planar shape, and may be staggered such that the
actuator units 7 may avoid the ink supply ports 9 in the upper
surface 5a of the passage unit 5. The longer sides of the
respective trapezoidal planar-shaped actuator units 7 may be
arranged along the lengthwise direction of the passage unit 5, such
that the long sides of two actuator units 7, which sandwich another
one actuator unit 7, may be flush with each other.
[0052] Referring to FIG. 10A, the actuator units 7 each may include
a plurality of, e.g., three piezoelectric sheets 71, 72, and 73
made of a ferroelectric ceramic material, e.g., titanate zirconate
(PZT). The piezoelectric sheets 71, 72, and 73 each may have a
thickness of approximately 15 .mu.m. The piezoelectric sheets 71,
72, and 73 may be disposed over the many pressure chambers 53
arranged for each ink ejecting area 5b.
[0053] The individual electrode 76 may be arranged on the upper
piezoelectric sheet 71, and may correspond to each pressure chamber
53. A common electrode 75 may be interposed between the upper
piezoelectric sheet 71 and the underlying piezoelectric sheet 72,
and may be configured to cover the entire surface of each sheet.
The common electrode 75 may have a thickness of approximately 2
.mu.m, and may be held substantially at ground potential. The
individual electrodes 76 and the common electrode 75 may be made of
a metallic material, e.g., Ag--Pd. Piezoelectric sheets 72 and 73
may have no electrodes arranged between them.
[0054] Each individual electrode 76 may have a thickness of
approximately 1 .mu.m. Referring to FIG. 10B, the individual
electrode 76 may have a substantially rhomboid planar shape,
similar to the shape of the pressure chamber 53. One of the acute
portions of the substantially rhomboid individual electrode 76 may
be extended. The extended portion of individual electrode 76 may be
provided with a circular land 77, which may have a diameter of
approximately 160 .mu.m, and which may be electrically connected to
the individual electrode 76. The land 77 may be made of a gold
containing, e.g., glass frit. Referring to FIG. 1, the respective
lands 77 may be connected to the driver ICs 6a through the FPCs 6.
Consequently, the potentials of the individual electrodes 76 may be
selectively controlled.
[0055] To drive the actuator units 7, according to an embodiment of
the invention, first, the piezoelectric sheet 71 may be polarized
in the thickness direction. Accordingly, when the individual
electrode 76 and the common electrode 75 are set to different
potentials, and an electric field is applied to part of the upper
piezoelectric sheet 71 between the individual electrode 76 and the
common electrode 75 in the polarization direction, the
electric-field-applied portion may function as an active portion
that may deform due to a piezoelectric effect. The other two
piezoelectric sheets 72 and 73 each may serve as an inactive layer
having no region sandwiched between the individual electrode 76 and
the common electrode 75. Accordingly, the sheets 72 and 73 may not
voluntarily deform. In other words, each actuator unit 7 may be a
unimorph type, consisting of a layer containing active portions and
an inactive layer.
[0056] Referring to FIG. 10A, the piezoelectric sheets 71 to 73 may
be fixed to the upper surface of the cavity plate 61 including the
pressure chambers 53. Accordingly, when the deformation of the
portion of the upper piezoelectric sheet 71 in which an electric
field has been applied, differs from that of the underlying parts
of the piezoelectric sheets 72 and 73 relative to the direction
along the surfaces of the sheets thereto, all of the piezoelectric
sheets 71 to 73 may deform toward the pressure chamber 53, e.g.,
unimorph deformation may occur. At that time, the capacity of the
pressure chamber 53 may decrease, such that the pressure in the
pressure chamber 53 then may rise. Consequently, ink may be
squeezed out of the pressure chamber 53, to the corresponding
nozzle 8, which may cause ink droplets to be ejected from the
nozzle 8. After that, when the individual electrode 76 is set to
the same potential as that of the common electrode 75, the
piezoelectric sheets 71 to 73 may return to their original states,
e.g., their flattened states, such that the capacity of the
pressure chamber 53 may return to its original capacity. Thus, the
ink may be introduced from the manifold passage 51 to the pressure
chamber 53, such that the ink may be stored in the pressure chamber
53.
[0057] In the manufacture of the upper reservoir block 11, when the
excess film 90 may be cut off from the edge of the side wall 33 of
the protuberance 31, and the excess film 90 may be cut off from the
edge of the loop projection 41 using a cutter, there is no obstacle
in each cutting path, because, as described above, the level of
each rib 35 may be lower than that of the side wall 33 of the
protuberance 31 and the level of each rib 45 may be lower than that
of the loop projection 41, the ribs 35 may be separated from the
the ends of the side wall 33, and the ribs 45 may be separated from
the loop projection 41. Thus, the cutting operation can easily be
performed. Furthermore, the occurrence of a cutting mistake caused
by hitting the blade of the cutter against the ribs 35 or 45 may be
prevented, which may increase the manufacturing yield.
[0058] When the excess film 90 is cut off using a laser beam, the
excess film 90 may be prevented from being welded to the ribs 35 or
45. Consequently, the step of removing the film 90 welded to the
ribs 35 or 45 may be eliminated, which may improve efficiency of
the cutting operation.
[0059] In the ink jet head 1 according to the present embodiment,
some of the ribs 35 may be connected to the external surface 33b of
the side wall 33 of the protuberance 31. Some of the ribs 45 may be
connected to the outer surface 41b of the loop projection 41.
Accordingly, the reinforcing effect by the ribs 35 and 45 may be
increased.
[0060] As mentioned above, in each of the specific ribs 35,
therefore, the level of parts which may be located in the cutting
path for cutting the film 90 may be lowered below the level of the
side wall 33 of the protuberance 31 extending from the upper
reference surface 12a. Similarly, in each of the specific ribs 45,
the level of parts which may be located in the cutting path may be
lowered than that of the loop projection 41. In each of the
specific ribs 35 and 45, the level of a part not located in the
cutting path may be higher than that of a part in the cutting path.
Consequently, the reinforcing effect by the ribs 35 and 45 may be
further improved, and the film 90 may be cut efficiently. Thus, the
solidity of the upper reservoir block 11 may be held
sufficiently.
[0061] In the ink jet head 1 according to the present embodiment,
the level of a portion in which the notch 35a is not arranged, of
each specific rib 35 is at or below the level of the side wall 33
of the protuberance 31. Similarly, the level of a portion in which
the notch 45a is not arranged, of each specific rib 45 is at or
below the level of the loop projection 41. Therefore, during
welding of the films 13 and 14 to the main body 12, if the unrolled
film 90 is pressed against each of the side wall 33 and the loop
projection 41 so as to cover the passage openings 34 and 44, the
ribs 35 and 45 may not obstruct the operation. Furthermore, a tool
that heats the films 13 and 14 for welding may not contact the ribs
35 and 45. Accordingly, the ribs 35 and 45 may not obstruct the
operation of welding the films 13 and 14.
[0062] In the foregoing embodiment, the ribs 35 may be connected to
the external surface 33b of the side wall 33 of the protuberance
31, and the ribs 45 may be connected to the outer surface 41b of
the loop projection 41. Nevertheless, in another embodiment, it may
be unnecessary to connect the ribs 35 to the external surface 33b
of the side wall 33, and it also may be unnecessary to connect the
ribs 45 to the outer surface 41b of the loop projection 41.
[0063] In the foregoing embodiment, the specific ribs 35 and 45 may
have the notch 35a and 45a, respectively. Nevertheless, in another
embodiment, when the ribs 35 are not connected to the external
surface 33b of the side wall 33 and the ribs 45 are not connected
to the outer surface 41b of the loop projection 41, it may be
unnecessary to form the notches 35a and 45a. The level of each of
the ribs 35 and 45 may be made uniform.
[0064] Having described the preferred embodiment of the present
invention, it should be understood that the invention is not
limited to the above-described embodiment and various changes and
modifications thereof may be made without departing from the sprit
or scope of the invention as defined in the appended claims.
* * * * *